[codex] Align workflow docs and close CoT loader plan

[steveya]

Summary

• simplify AGENTS.md so Alphaforge inherits the shared workspace workflow and keeps only repo-specific guidance
• migrate queue-driving plan docs to the status-prefixed doc/plan/ naming scheme
• close the CFTC commodity CoT completion plan and clarify the raw cftc.cot.disagg entity/column contract in the public docs

Why

The workspace workflow was consolidated at the root, so the repo-local guide should stop duplicating shared process. While migrating the plan mirror, the active CFTC commodity CoT workstream also needed to be closed based on the audit result: the loader already existed and the remaining gap was documentation drift in the raw-loader example contract.

Impact

• future agents pick up the shared implementation/planning workflow from the workspace root
• Alphaforge plan mirrors now advertise draft/active/done status in their filenames
• public-web CoT docs now teach the correct raw loader entity_id and metric columns

Validation

• /Users/steveyang/miniforge3/bin/python -m pytest tests/public_web/test_cftc_cot.py -q
• /Users/steveyang/miniforge3/bin/python -m pytest tests/test_cftc_dtcc_adapter.py -q -k disagg
• /Users/steveyang/miniforge3/bin/python -m mkdocs build --strict